/Engine/Plugins/FX/Niagara/Source/Niagara/Public/NiagaraDataChannelAccessor.h
Adds a new item to be written to the correct data channel group based on the search params. Returns the group index this item now belongs to.
int32 AddItem ( [UWorld](API\Runtime\Engine\Engine\UWorld) * World, const [UNiagaraDataChannel](API\Plugins\Niagara\UNiagaraDataChannel) * NDC, const [FNiagaraDataChannelSearchParameters](API\Plugins\Niagara\FNiagaraDataChannelSearchParamet-) & ItemSearchParams )